Hearing that Charlotte's little sister is in trouble, Allen and the others rush over to Allen's hometown. They're welcomed by Allen's uncle, Harvey, and his aunt, Liselotte. As they figure out Natalia's situation, they're forced to pretend being lovers.
So, by Charlotte's little 
sister, you mean...
...إذًا، تقصدين بأخت شارلوت الصغرى
Was ist Charlottes Schwester
für eine Person?
Et donc,
la petite sœur de Charlotte…
E quindi, la sorella minore di Charlotte sarebbe...
Bom, essa irmãzinha da Charlotte...
Значит, младшая сестра Шарлотты...